How to Get Rid of Mice in the House: Traps, Sealing, and Cleanup

If you hear scratching in the walls at night or find small droppings in a drawer, you likely have mice. To get rid of them, set plenty of snap traps along the walls, bait them with peanut butter, seal every hole bigger than 1/4 inch, and clean up droppings the safe way. Traps solve today's problem, and sealing solves next month's.

Fall is the busiest time for mice. When nights get cold, they look for a warm place with food. Your house is a good match. This guide shows you how to find them, catch them, keep them out, and clean up safely.

Signs you have mice

You may never see a mouse. They hide in the day and come out when the house is quiet. Look for these clues:

• Droppings. Mouse droppings are small and dark, about the size of a grain of rice, with pointed ends. UC IPM says one mouse can leave around 50 droppings a day. Check along walls, in cabinets, and behind the stove.
• Scratching or squeaking in the walls, ceiling, or under floors, mostly at night.
• Gnawed food packages. Chewed cereal boxes, bread bags, and pet food bags are a common sign.
• Nests. Mice shred paper, fabric, and insulation to make a ball-shaped nest in quiet places.
• A musty, stale smell, often strongest in a closet or cabinet. If the smell is more like sewage, see our guide on a sewage smell in the house.
• Grease marks along walls where they run every night.
• Pet behavior. A dog or cat that stares at a wall or sniffs one spot may hear or smell mice.

Why one mouse becomes many

Mice breed fast. UC IPM reports that pups are born about 18 to 21 days after mating, and they can have babies of their own at 5 to 6 weeks old. One female can have 5 to 10 litters a year, with about 5 or 6 pups each.

That is why waiting makes things worse. A small problem in October can be a big problem by spring.

How mice get in

The CDC says mice can squeeze through a hole as small as a pencil is wide, about 1/4 inch. If your finger fits, a mouse fits. Common entry points include:

• Gaps around pipes under sinks and behind washers
• Gaps around dryer vents and gas lines
• Holes where cables or wires enter the house
• Cracks in the foundation
• Gaps under doors, especially garage doors
• Missing or loose mesh on vents and crawl space openings
• Gaps where the siding meets the foundation

Step 1: Gather your supplies

You do not need much:

• 6 to 12 snap traps. Use more traps than you think you need.
• Peanut butter. It is a favorite bait, and it sticks to the trap.
• Gloves and a flashlight.
• Steel wool, caulk, and metal mesh for sealing.
• Paper towels, trash bags, and bleach for cleanup.

Step 2: Set snap traps the right way

Snap traps that you set by pressing or squeezing the back are the safest option for homes with kids. Place them like this:

1. Put traps along walls. Mice run close to walls, so set each trap with the trigger end touching the wall.
2. Set them where you saw droppings. That is where mice travel.
3. Use a pea-sized dab of peanut butter. More than that lets the mouse lick it off without setting the trap.
4. Space traps close together. Penn State Extension suggests traps about 10 feet apart or closer in areas with signs of mice. Set them in pairs in busy spots.
5. Keep traps out of reach of kids and pets. Slide them behind appliances or inside a covered box with a mouse-sized hole.
6. Check them every day. Remove any mouse and reset the trap.

Wear gloves when you handle traps. Place a caught mouse in a sealed bag and put it in the outdoor trash.

Step 3: Take away food and water

Mice come in for easy food. Cut off the supply and traps work better.

• Store dry food in tight containers. Use glass, metal, or hard plastic. Mice chew through bags and cardboard.
• Clean crumbs from counters, the floor, and the stove top each night.
• Do not leave pet food out overnight. If you have a new pet, our guide to preparing your home for a new pet has tips for safe food storage.
• Take trash out often and use a lid.
• Fix drips. Mice need water too.

Step 4: Seal the holes

Sealing is the most important step for the long run. The CDC says to fill small holes with steel wool, then put caulk around it to hold it in place. You can also use spray foam made for pest control. For larger holes, use hardware cloth, metal sheeting, or cement.

Go through the house with a flashlight and check these places:

• Under kitchen and bathroom sinks
• Around the water heater and furnace
• Where pipes and wires pass through walls or floors
• Around the outside of the foundation
• Garage door edges and the seal at the bottom
• Dryer and attic vents

While you are sealing, you are also closing air leaks. That helps your heating bill, too. Our guide to hunting down air leaks shows where drafts hide. For small cracks in walls and ceilings, see how to judge which wall cracks are worth worrying about.

Seal the holes after you have trapped the mice already inside. Otherwise you could lock them in and make them chew new ways out.

Step 5: Clean up the safe way

Mouse droppings, urine, and nests can carry germs. The CDC explains that hantavirus spreads through contact with rodent urine, droppings, and saliva, or by breathing in dust that has been stirred up. Hantavirus illness is rare, but it can be serious. Clean up with care:

1. Open doors and windows for about 30 minutes before you start, and leave the room while it airs out.
2. Put on rubber or plastic gloves.
3. Mix a bleach solution. The CDC says to use 1.5 cups of household bleach in 1 gallon of water.
4. Spray droppings, urine, and nests until very wet. Let it soak for 5 minutes.
5. Wipe up with paper towels, put them in a bag, and seal it.
6. Mop or wipe the area with the same solution.
7. Take off gloves, throw them away, and wash your hands well with soap and water.

What does not work well

Many "mouse cures" are popular but do not solve the problem:

If you like peppermint oil, use it as a small extra next to traps and sealing, not instead of them.

Should you use poison?

Poison baits can work, but they come with risks. A mouse may die in a wall and cause a strong smell for a week or more. Pets and wildlife can also be harmed if they eat a poisoned mouse. For most homes, snap traps and sealing are the safer choice. If you do use bait, choose tamper-resistant bait stations and keep them out of reach of kids and pets.

How long does it take?

Plan on one to two weeks of steady trapping for a small problem. Keep traps set until you have gone a full week with no catches and no new droppings. Then keep a few traps in the garage and basement through the winter.

When to call a pest control pro

Call a professional if:

• Traps keep catching mice after two weeks
• You see mice in the daytime, which can mean a large group
• You find droppings in many rooms
• You hear mice in walls or ceilings that you cannot reach
• You cannot find where they are getting in
• You see signs of rats, such as larger droppings or gnaw marks on wood

A good pro will find the entry points, set up traps, and give you a plan to stop mice from coming back.

Mice and your health

Mice can leave droppings on food and counters, which may spread germs. They also chew wires, which is a fire risk. If you find signs of mice in a kitchen, throw away any food that was gnawed or touched, and wipe counters and shelves with a disinfectant.

If you have a cough, fever, or trouble breathing in the weeks after cleaning up a large mouse problem, tell your doctor about the exposure. Early care matters with hantavirus.

Keep mice out for good

Once your house is clear, a few habits keep it that way:

• Trim bushes and branches that touch the house, since mice use them like a bridge.
• Stack firewood away from the walls, at least 20 feet if you can.
• Keep the yard clear of piles of leaves and clutter near the foundation.
• Check seals each fall, before mice go looking for a winter home.
• Keep garage doors closed and replace worn door seals.

Bugs also look for a warm home in fall. If you are seeing them too, read our guides on getting rid of stink bugs and ladybugs in the house. Sealing cracks helps with all of them.

The bottom line

To get rid of mice, trap them and seal the holes. Set snap traps along walls with peanut butter, check them every day, and keep going for at least a week after the last catch. Fill every opening bigger than 1/4 inch with steel wool and caulk. Clean up droppings with a bleach solution and paper towels, never a broom or vacuum. If the problem lasts past two weeks, call a pro.